This class is NOT recommended for new users and should be
considered UNSUPPORTED.

In Solr 1.2, DateField did not enforce
the canonical representation of the ISO 8601 format when parsing
incoming data, and did not generation the canonical format when
generating dates from "Date Math" strings (particularly as
it pertains to milliseconds ending in trailing zeros) -- As a result
equivalent dates could not always be compared properly.

This class is provided as possible alternative for people who depend on
the "broken" behavior of DateField in Solr 1.2
(specificly: accepting any input that ends in a 'Z', and
formating DateMath expressions using 3 decimals of milliseconds) while
still supporting some newer functionality of DateField (ie: DateMath on
explicit strings in addition to "NOW")

Users that desire 100% backwards compatibility should consider using
the Solr 1.2 version of DateField